quick-xml

High performance xml pull reader/writer.

The reader: - is almost zero-copy (use of Cow whenever possible) - is easy on memory allocation (the API provides a way to reuse buffers) - support various encoding, namespaces resolution, special characters.

docs.rs

Syntax is inspired by xml-rs.

Usage

toml [dependencies] quick-xml = "0.9.4" rust extern crate quick_xml;

Example

Reader

```rust use quickxml::reader::Reader; use quickxml::events::Event;

let xml = r#" Test Test 2 "#;

let mut reader = Reader::fromstr(xml); reader.trimtext(true);

let mut count = 0; let mut txt = Vec::new(); let mut buf = Vec::new();

// The Reader does not implement Iterator because it outputs borrowed data (Cows) loop { match reader.readevent(&mut buf) { Ok(Event::Start(ref e)) => { match e.name() { b"tag1" => println!("attributes values: {:?}", e.attributes().map(|a| a.unwrap().value).collect::>()), b"tag2" => count += 1, _ => (), } }, Ok(Event::Text(e)) => txt.push(e.unescapeanddecode(&reader).unwrap()), Ok(Event::Eof) => break, // exits the loop when reaching end of file Err(e) => panic!("Error at position {}: {:?}", reader.bufferposition(), e), _ => (), // There are several other Events we do not consider here }

// if we don't keep a borrow elsewhere, we can clear the buffer to keep memory usage low
buf.clear();

} ```

Writer

```rust use quickxml::writer::Writer; use quickxml::reader::Reader; use quick_xml::events::{Event, BytesEnd, BytesStart}; use std::io::Cursor; use std::iter;

let xml = r#"text"#; let mut reader = Reader::fromstr(xml); reader.trimtext(true); let mut writer = Writer::new(Cursor::new(Vec::new())); let mut buf = Vec::new(); loop { match reader.readevent(&mut buf) { Ok(Event::Start(ref e)) if e.name() == b"thistag" => {

        // crates a new element ... alternatively we could reuse `e` by calling
        // `e.into_owned()`
        let mut elem = BytesStart::owned(b"my_elem".to_vec(), "my_elem".len());

        // collect existing attributes
        elem.extend_attributes(e.attributes().map(|attr| attr.unwrap()));

        // copy existing attributes, adds a new my-key="some value" attribute
        elem.push_attribute(("my-key", "some value"));

        // writes the event to the writer
        assert!(writer.write_event(Event::Start(elem)).is_ok());
    },
    Ok(Event::End(ref e)) if e.name() == b"this_tag" => {
        assert!(writer.write_event(Event::End(BytesEnd::borrowed(b"my_elem"))).is_ok());
    },
    Ok(Event::Eof) => break,
// you can use either `e` or `&e` if you don't want to move the event
    Ok(e) => assert!(writer.write_event(&e).is_ok()),
    Err(e) => panic!("Error at position {}: {:?}", reader.buffer_position(), e),
}
buf.clear();

}

let result = writer.intoinner().intoinner(); let expected = r#"text"#; asserteq!(result, expected.asbytes()); ```

Performance

Benchmarking is hard and the results depend on your input file and your machine.

Here on my particular file, quick-xml is around 50 times faster than xml-rs crate.

``` // quick-xml benches test benchquickxml ... bench: 256,921 ns/iter (+/- 18,306) test benchquickxmlescaped ... bench: 324,320 ns/iter (+/- 19,968) test benchquickxmlnamespaced ... bench: 396,318 ns/iter (+/- 23,663)

// same bench with xml-rs test benchxmlrs ... bench: 14,839,533 ns/iter (+/- 2,377,647) ```

For a feature and performance comparison, you can also have a look at RazrFalcon's choose-your-xml-rs.

Contribute

Any PR is welcomed!

License

MIT